1. Field of the Invention
Embodiments relate to an organic light-emitting display device. Also, embodiments relate to a method of driving an organic light-emitting display device.
2. Discussion of the Related Art
Devices for displaying information are being widely developed. The display devices include liquid crystal display (LCD) devices, organic light-emitting display (OLED) devices, electrophoresis display devices, field emission display (FED) devices, and plasma display devices.
Among these display devices, OLED devices have the features of lower power consumption, wider viewing angle, lighter weight and higher brightness compared to LCD devices. As such, the OLED device is considered to be next generation display devices.
FIG. 1 is a block diagram showing an OLED device according to the related art.
Referring to FIG. 1, the OLED device of the related art includes an organic light emission panel 101, a gate driver 110, a data driver 120 and a timing controller 130.
A plurality of gate lines GL1˜GLn are formed on the organic light emission panel 101. Also, a plurality of data lines DL1˜DLm extending in a direction crossing the gate lines GL1˜GLn are formed on the organic light emission panel 101.
The plurality of gate lines GL1˜GLn are electrically connected to the gate driver 110. The plurality of data lines DL1˜DLm are electrically connected to the data driver 120.
The gate driver 110 uses signals applied from the timing controller 130 and applies a gate voltage to the organic light emission panel 101 through the gate line GL.
The data driver 120 uses signals applied from the timing controller 130 and applies data voltages to the organic light emission panel 101 through the data lines DL.
The heat generation caused by driving the related art OLED device becomes a big issue. More particularly, the heat generation in the data driver, which is being fabricated in an integrated circuit chip shape, becomes a large problem. In order to solve the heat generation of the data driver and enhance a data charging property, a charge-sharing method allowing adjacent pixels to share electric charges with each other and a pre-charging method enabling an externally fixed voltage to be input prior to the data voltage are proposed. The charge-sharing and the pre-charging are being used alone or together.
FIG. 2 is a circuit diagram showing the connection configuration of a data driver according to the related art.
As shown in FIG. 2, the related art data driver includes a data latch 151 and a plurality of DACs (Digital-to-Analog Converters) 153.
The data latch 151 sequentially latches data signals applied from the timing controller. Also, the data latch 151 simultaneously outputs the latched data signals for a single horizontal line in response to a source output enable signal from the timing controller.
The plurality of DACs 153 converts a single horizontal line of data signal applied from the data latch 151 into analog data voltages. The analog data voltages are transmitted from the DACs 153 to the plurality of data lines DL.
The data lines DL are used to transfer the data voltages to the organic light emission panel. Each data line DL is electrically connected to the respective DAC 153 through a switch 155. The switch 155 replies to an output enable signal OE and transfers the data voltage from the respective DAC 153 to the respective data line on the organic light emission panel.
The data driver further includes a charging line 161 extending in a direction crossing the data lines DL. A charging voltage Vpre is applied to one end of the charging line 161. A charging capacitor 163 connected to the charging line 161 has a function of charging electric charges for a pre-charging and a charge sharing. The charging line 161 is electrically connected to the data lines DL through a plurality of charging switches 157. The plurality of charging switches 158 are controlled by a charging control signal Pre applied from the timing controller. The charging control signal Pre and the output enable signal OE are opposite to each other in waveform. When the charging control signal Pre has a high level, the pre-charging and the charge-sharing are performed for the data lines DL. On the contrary, if the output enable signal OE has a high level, the data voltages are applied from the DACs 153 to the data lines DL.
FIG. 3 is a waveform diagram illustrating the voltage variation of a data line in accordance with a charging control signal and an output enable signal of the related art.
DL(a) of FIG. 3 shows voltage state on the data line DL when the pre-charging and the charge-sharing are not performed. DL(b) shows voltage state on the data line DL when the pre-charging and the charge-sharing are performed.
The charging control signal Pre has the high level in a fixed interval whenever a fixed period elapsed. The output enable signal OE has the low level when the charging control signal Pre maintains the high level. Also, the output enable signal OE maintains the high level during the low level interval of the charging control signal Pre.
The data voltage transitions from a high voltage to a low voltage on the basis of the charging voltage Vpre when a first period is exchanged with a second period. At this time, the charge-sharing is performed in response to the charging control signal Pre during the fixed interval, so that power is recovered. When a third period is exchanged with a fourth period, the data voltage rises from the low voltage to high voltage on the basis of the charging voltage Vpre and the pre-charging is performed in response to the charging control signal Pre during the fixed interval. As such, power consumption is reduced.
It is unnecessary to perform the pre-charging and the charge-sharing when a second or fourth period is exchanged with a third or fifth period. Nevertheless, the charging control signal Pre forces the pre-charging or the charge-sharing to be performed. Due to this, power consumption increases. Moreover, the unnecessarily performed pre-charging or charge-sharing causes the data driver to generate large amounts of heat.